Scaffolding provides a temporary elevated platform that is used in the construction or repair of a building. Scaffolding provides a work platform where workers can access elevated portions of a wall, ceiling or roof. A typical use for scaffolding is the laying of masonry on the outside of a building.
One type of scaffolding utilizes a fixed framework to support the work platform. Once the scaffolding is erected, the work platform is fixed in elevation. To move the work platform up or down, the supporting framework must be rearranged by either adding additional framework to raise the platform or remove the upper portions of the framework to lower the elevation. Moving the work platform up or down is a time consuming procedure.
Another type of scaffolding utilizes a vertical tower structure. The work platform is mounted on the tower and is provided with motors to propel the work platform up and down the tower. This mobile scaffolding platform reduces the time needed to change elevations because the tower structure need not be rearranged for changing elevation. The work platform merely traverses up and down the tower.
The mobile work platform and tower arrangement have a maximum load limit. In a common commercial mobile work platform, the maximum load limit is about 8,000 pounds. For masonry work, this maximum load limit provides enough bricks for only a few hours of work. Consequently, the work platform must be reloaded frequently.
Thus, although the mobile work platform is an improvement over fixed scaffolding, it presents a problem in being resupplied. A typical day for a mobile work platform begins by loading the first load of bricks and workers onto the platform at ground level early in the morning. The lower platform then slowly climbs the tower to the work area, where the workers lay the bricks. When the load of bricks on the platform has been exhausted, the workers must stop and bring the empty platform back down to the ground to be reloaded. The round trip time to the ground for reloading and back to the work area may take as long as an hour because of the slow speed of travel of the work platform. Several such trips down to the ground for reloading in a single day reduces productivity because the workers are idled during this time.
One prior art method of resupplying the work platform at an elevated location involves bringing in a crane to lift cargo up to the work platform. While this technique reduces the number of trips to the ground by the work platform, it is expensive to implement because it requires additional heavy equipment and operators. Furthermore, there are situations where, due to the worksite, use of a crane is impracticable. Another prior art method of resupplying the work platform at elevated locations involves bringing the cargo up through the interior of the building. The cargo is brought out to the work platform, which is on the outside of the building, by window. This is a roundabout method of moving the cargo around and adds to the difficulty of loading the cargo. The implementation of this technique depends on the availability of a window. If there is no window through which to pass the cargo, then this technique cannot be used.